Increased urinary endothelin-1 excretion in newly diagnosed type 2 diabetic patients

To investigate whether urinary and plasma endothelin (ET)-1 concentrations are responsive to the alteration of intravascular blood volume in uncontrolled diabetic patients, we determined urinary ET-1 excretion and plasma ET-1 concentration in 42 newly diagnosed type 2 diabetic patients and 38 normal subjects. Mean fasting plasma glucose value (12.8 +/- 0.72 mmol l-1) and plasma renin activity (PRA, 2.80 +/- 0.44 ng ml-1 hr-1) in diabetic patients were significantly higher as compared to normal controls (mean plasma glucose value: 5.2 +/- 0.83 mmol l-1; mean PRA value: 1.34 +/- 0.17 ng ml-1 hr-1), whereas plasma ET-1 value (1.33 +/- 0.07 pmol l-1) was not significantly different from that (1.29 +/- 0.06 pmol l-1) of normal controls. Mean urinary ET-1 excretion level (7.53 +/- 0.74 nmol mol-1 creatinine) was significantly higher than that (5.36 +/- 0.37 nmol mol-1 creatinine) of normal controls. Urinary ET-1 excretion was correlated with plasma glucose value (r = 0.360, p < 0.05) and PRA value (r = 0.381, p < 0.05). Urinary ET-1 excretion rate (5.17 +/- 0.37 nmol mol-1 creatinine) and PRA value (1.42 +/- 0.18 ng ml-1 hr-1) declined to normal levels when mean plasma glucose value decreased to the level of 7.1 +/- 0.39 mmol l-1 in diabetic patients after 4 months of glycemic control. Our results indicated that renal-derived ET-1 was responsive to the alteration of intravascular blood volume in untreated newly diagnosed type 2 diabetic patients.